Slow Brake Grind
 

hey folks,
I've just replaced calipers, rotors, pads and hoses all the way around on my 1984 300DT. They work very well at all speeds. However, I do feel a little bit of grinding from 5mph down to stopped. I've visually checked the rotors for scoring, but there isn't any. Any insights on this one?

Thanks,

Joey Hundert
1984 300DT (Running 35% Biodiesel (winter blend))

Did you bed the brake pads in by making half a dozen successive firm stops from highway speed, say, 65 mph? That might help.

Russ M

Did you put back the brake shims?

Yes,
I put the shims (by this I suppose you mean the pins and the anti-rattle spring) back, and promptly made about 12 stops from 70mph, full force. They perform so well, I was truly surprised - thats a lot of mass to haul down so quickly! I'll have her on jacks in about 2 days, so I'm going to inspect more closely.

Thanks so far,

Joey Hundert
1984 300D burnin' grease

does you car have ABS?
and is it that kind of pulsating grinding or is it more menacing.

which if you did and it was might mean a bad wheel speed sensor.
or less likley somthings bad somewhere else in ABS system -pumping brake's when it should not.

I mean the metal plates that are on the back of the brake pads. Mine had them on the previous brake pads, but re-used them from the previous set of used brake pads. Mine are the ATE fixed caliper type-'92 400E. I do not know if that makes a difference. I am guessing it shouldn't. If you do. You should apply MB brake grease, if recommended for your model. You might also want to check your rotors and wheel bearings also.

I, too, have a similar problem with my 92 500sel.

Brakes seem to work fine EXCEPT a metal to metal grinding noise (just like worn brakes) from 5mph or less ONLY. No grinding, pulsing, or noise anywhere else.

The brakes were done (just before I bought the car 10k miles ago), and the pads appear to have plenty of meat and there are no scores are other apparent wear to the rotors...

-David

That's not a good way to break-in new brakes! You should have made a number of moderate stops from about 25-30 Mph, (while letting the brakes cool in between) then a few more moderate stops from about 45-50 Mph to break them in.

You could have damaged or cracked the pads the way you broke them in and that's why they're making a grinding sound...

Did you use new rotors? Or, were the old ones turned? A lip at the edge of the rotor along with new pads could also cause the problem you're describing.

Bed in brake pads
-Stop 5 to 8 times from 50 to 25 mph (80 to 40 kph)
with light pedel pressure.
-Allow brakes to cool between application.
-Avoid hard stops during this procedure.